)]}'
{"/COMMIT_MSG":[{"author":{"_account_id":1849,"name":"Joe Gordon","email":"joe.gordon0@gmail.com","username":"jogo"},"change_message_id":"4b7921d7a9d4c155627cbdf3915201515439130b","unresolved":false,"context_lines":[{"line_number":13,"context_line":""},{"line_number":14,"context_line":" - Admin wishes to pull in newer libvirt version to address"},{"line_number":15,"context_line":"   a bug, but does not want any change in behaviour of nova"},{"line_number":16,"context_line":"   by having it use different libvirt features"},{"line_number":17,"context_line":""},{"line_number":18,"context_line":" - Admin is running a cloud with a variety of base OS versions"},{"line_number":19,"context_line":"   and wants Nova to use the same libvirt feature set across"}],"source_content_type":"text/x-gerrit-commit-message","patch_set":2,"id":"7ac7a964_f0b4f9f3","line":16,"updated":"2014-08-14 18:19:15.000000000","message":"Can you elaborate on this? The fact that changing libvirt  versions can automatically change behavior in a way that an admin may be concerned is a bit surprising.","commit_id":"6306bfc09ded5d902ea2b99d56bfb76f82fbc9d1"},{"author":{"_account_id":1779,"name":"Daniel Berrange","email":"berrange@redhat.com","username":"berrange"},"change_message_id":"e2fc5989f6fd638456be1f1e79b3f89a9e50c58c","unresolved":false,"context_lines":[{"line_number":13,"context_line":""},{"line_number":14,"context_line":" - Admin wishes to pull in newer libvirt version to address"},{"line_number":15,"context_line":"   a bug, but does not want any change in behaviour of nova"},{"line_number":16,"context_line":"   by having it use different libvirt features"},{"line_number":17,"context_line":""},{"line_number":18,"context_line":" - Admin is running a cloud with a variety of base OS versions"},{"line_number":19,"context_line":"   and wants Nova to use the same libvirt feature set across"}],"source_content_type":"text/x-gerrit-commit-message","patch_set":2,"id":"7ac7a964_1308862c","line":16,"in_reply_to":"7ac7a964_f0b4f9f3","updated":"2014-08-15 09:19:53.000000000","message":"An example is the snapshot feature we all know about. If you have libvirt \u003c 1.0.0 it will use the code path where VMs are shut off while the snapshot is taken, while newer libvirt we take a live snapshot while it is running. So if you updated libvirt for some bug fix you would see a functional change in the way snapshot work\n\nAnother example was CPU modelling - with older libvirt we had to setup CPU models one way, and with newer libvirt we set them up a different way. These two approaches are *almost* functionally equivalent, but not quite. So if you updated libvirt on one host, that host would potentially no longer be migration compatible with the older host.","commit_id":"6306bfc09ded5d902ea2b99d56bfb76f82fbc9d1"},{"author":{"_account_id":1849,"name":"Joe Gordon","email":"joe.gordon0@gmail.com","username":"jogo"},"change_message_id":"4b7921d7a9d4c155627cbdf3915201515439130b","unresolved":false,"context_lines":[{"line_number":15,"context_line":"   a bug, but does not want any change in behaviour of nova"},{"line_number":16,"context_line":"   by having it use different libvirt features"},{"line_number":17,"context_line":""},{"line_number":18,"context_line":" - Admin is running a cloud with a variety of base OS versions"},{"line_number":19,"context_line":"   and wants Nova to use the same libvirt feature set across"},{"line_number":20,"context_line":"   all nodes despite some nodes having newer libvirt."},{"line_number":21,"context_line":""}],"source_content_type":"text/x-gerrit-commit-message","patch_set":2,"id":"7ac7a964_10ba55de","line":18,"updated":"2014-08-14 18:19:15.000000000","message":"OS\u003doperating system?","commit_id":"6306bfc09ded5d902ea2b99d56bfb76f82fbc9d1"},{"author":{"_account_id":1779,"name":"Daniel Berrange","email":"berrange@redhat.com","username":"berrange"},"change_message_id":"e2fc5989f6fd638456be1f1e79b3f89a9e50c58c","unresolved":false,"context_lines":[{"line_number":15,"context_line":"   a bug, but does not want any change in behaviour of nova"},{"line_number":16,"context_line":"   by having it use different libvirt features"},{"line_number":17,"context_line":""},{"line_number":18,"context_line":" - Admin is running a cloud with a variety of base OS versions"},{"line_number":19,"context_line":"   and wants Nova to use the same libvirt feature set across"},{"line_number":20,"context_line":"   all nodes despite some nodes having newer libvirt."},{"line_number":21,"context_line":""}],"source_content_type":"text/x-gerrit-commit-message","patch_set":2,"id":"7ac7a964_8500c902","line":18,"in_reply_to":"7ac7a964_10ba55de","updated":"2014-08-15 09:19:53.000000000","message":"Yep","commit_id":"6306bfc09ded5d902ea2b99d56bfb76f82fbc9d1"},{"author":{"_account_id":1849,"name":"Joe Gordon","email":"joe.gordon0@gmail.com","username":"jogo"},"change_message_id":"4b7921d7a9d4c155627cbdf3915201515439130b","unresolved":false,"context_lines":[{"line_number":17,"context_line":""},{"line_number":18,"context_line":" - Admin is running a cloud with a variety of base OS versions"},{"line_number":19,"context_line":"   and wants Nova to use the same libvirt feature set across"},{"line_number":20,"context_line":"   all nodes despite some nodes having newer libvirt."},{"line_number":21,"context_line":""},{"line_number":22,"context_line":" - Admin wants to ensure their cloud deployment is only using"},{"line_number":23,"context_line":"   libvirt features that were tested by the OpenStack CI"}],"source_content_type":"text/x-gerrit-commit-message","patch_set":2,"id":"7ac7a964_70db891b","line":20,"updated":"2014-08-14 18:19:15.000000000","message":"Why would someone use a mix of base operating systems?  This is probably my lack of operational experience, but this seems a bit far fetched. Can you elaborate on this point.","commit_id":"6306bfc09ded5d902ea2b99d56bfb76f82fbc9d1"},{"author":{"_account_id":1779,"name":"Daniel Berrange","email":"berrange@redhat.com","username":"berrange"},"change_message_id":"e2fc5989f6fd638456be1f1e79b3f89a9e50c58c","unresolved":false,"context_lines":[{"line_number":17,"context_line":""},{"line_number":18,"context_line":" - Admin is running a cloud with a variety of base OS versions"},{"line_number":19,"context_line":"   and wants Nova to use the same libvirt feature set across"},{"line_number":20,"context_line":"   all nodes despite some nodes having newer libvirt."},{"line_number":21,"context_line":""},{"line_number":22,"context_line":" - Admin wants to ensure their cloud deployment is only using"},{"line_number":23,"context_line":"   libvirt features that were tested by the OpenStack CI"}],"source_content_type":"text/x-gerrit-commit-message","patch_set":2,"id":"7ac7a964_456311dc","line":20,"in_reply_to":"7ac7a964_70db891b","updated":"2014-08-15 09:19:53.000000000","message":"When you have a large cloud deployment, you aren\u0027t going to update all your compute nodes at the same time. You\u0027ll almost certainly have a period when there is a staggered set of versions in production.  Alternatively, you might be deploying new hardware that is only certified against a newer version of the OS, but don\u0027t wish to update all existing compute nodes to that new version. So you\u0027ll have multiple OS versions, and wish to ensure VMs have the same functional behaviour on all nodes despite potential different libvirt versions","commit_id":"6306bfc09ded5d902ea2b99d56bfb76f82fbc9d1"}]}